Ghost of Christmas Presents

My first love in science, the first thing that really interested me intellectually, was astronomy. It was early 1986, around the time I turned five. (I was a weird kid.) Anyway, I was really into Star Wars, and wanted to go to space and explore different planets. I had (and still have) a book, "Astronomy Today", with lots of great illustrations and diagrams; sure, I wasn't *reading it* reading it yet, but I got a lot out of those illustrations. Then I discovered that, contrary to the movies, we couldn't exceed the speed of light, so we were basically stuck here. It's a nice enough solar system, but, well, y'know... the realization was terribly disappointing, and space went from an obsession to a pleasant side interest (I still love going to the planetary science sessions when attending GSA annual meetings).

At the time, we had just moved to Tucson. There's a lot of difference geologically between southern Arizona and south-central Minnesota; for starters, a lot more of the geology is right there at the surface in Arizona, and a lot more of it is Mesozoic. Still, Arizona is not Dinosaur Central; it's more like a nice suburb. After nearly 40 years I can't say what it was about dinosaurs that caught my eye. Maybe it was the British Museum toys at the Arizona-Sonora Desert Museum. Whatever it was, the feedback loop started: kid shows interest, people around start feeding the interest, interest intensifies...

The step that sealed the interest in paleontology came at Christmas 1986. There was one rectangular gift with unusual heft. Under the wrapping paper was the Normanpedia, "The Illustrated Encyclopedia of Dinosaurs". Could I read it? Well, okay, sure, I was a great reader for five-and-a-half, but it's safe to assume it took some time and practice before I was conversant (and the book probably accelerated the process, so on top of his scientific accolades, David Norman can take some credit for improving at least one kid's  literacy). But don't forget the second word of the title! The restorations, the photos, the skeletal diagrams! I went through reams of paper tracing skeletons, then drawing outlines around them on the other side of the sheets. That way, there would be a skeleton on one side, a drawing on the other, and if I held the paper to the light, both of them would be there, skeleton revealed inside the body. I loved that book to death; it's in a box of mementos somewhere at home, dust jacket long gone, spine held together by heavy-duty tape, a slip of paper taped over the "dinosauroid" drawing because it creeped me out. I had to get a second copy in the Nineties because the first was falling apart. The second copy also started falling apart after about ten years, so now I'm on my third. Anyway, no particular moral or commentary or insight this time, just wanted to share some holiday nostalgia. See you in 2026!

What do Delaware, Hawaii, and Rhode Island have in common?

Answer: They are the only three U.S. states for which I can't find a record of a mastodon or mammoth.

Hawaii is not exactly a surprise. Certainly proboscideans can swim, but if you want a large mammal that can swim halfway across the Pacific Ocean without dying, it's going to look and function suspiciously like a cetacean instead.

Delaware and Rhode Island, on the other hand, doubtless had mammoths and mastodons tromping over them at some point, because they're surrounded by states (and submerged coastal plains) that have their fossils. They're just both small states not blessed with the most helpful geology, and mantled by urbanization. Rhode Island gets an additional strike from being subjected to glaciers. Someday the fossils will turn up, though. Maybe there's already something; maybe somebody has a funny-looking doorstop they found in 1973 and never paid much attention to, or there's a notice in a local paper published in 1989 about a couple of campers who found a tooth and turned it over to a local historical society, or somebody will hop into the comments of this post and say, "Hey, ya numbskull, ya missed this!"

Now, the nitty-gritty: every once in a while I'd wondered how many states have records of mammoths or mastodons, and occasionally puttered in a source or two. This time I decided to be more thorough. I checked the Hay inventories, Neotoma (which has the old FaunMap contents), and the Paleobiology Database for starters. These three together narrowed down the list of absences to Delaware, Hawaii, New Hampshire, and Rhode Island. If you're curious: Hay didn't have mammoths or mastodons in those four plus Maine and basically omitted Alaska, but had all the rest plus the District of Columbia; Neotoma was missing the four plus Alabama, Mississippi, North Dakota, Vermont, and D.C.; and the PBDB was missing the four plus Connecticut, Louisiana, Massachusetts, Maine, New Jersey, North Dakota, Vermont, and D.C. This is why it's important to check multiple sources; no one source has everything.

Putting aside Hawaii, that left Delaware, New Hampshire, and Rhode Island to check out. Now was the time to drill into the resources of various search engines and museum databases/iDigBio. For the record, I leaned on Google Scholar, Google Books, and the news tab of regular Google (not Google News), with various permutations of "mammoth", "mastodon", "Mammuthus", and "Mammut" plus a state, with additional terms as necessary to knock out particularly obnoxious false positives. This eliminated New Hampshire, which now has a record from a find on land after a couple of teeth found nearby offshore. For a short time I'd thought I'd found one for Delaware, thanks to a short piece in the Winter 1994 issue of "First State Geology" (p. 3). The article mentioned that Jeremy Cloutier of Milford had donated a mastodon tooth to the Delaware Geological Survey, but the tooth derived from offshore clam dredging and therefore doesn't count for our purposes. So, for now, we're still at Delaware, Hawaii, and Rhode Island. (Still a few field days 'til Christmas, if you're feeling like pulling off a Christmas miracle!)

"Archie", the world's largest mounted Columbian mammoth skeleton, on display in Elephant Hall, University of Nebraska State Museum.

A Visual Paleontological Inventory of Utah’s National Park Service Areas

Allow me to indulge in a bit of puffery and congratulations...

Let's go back a couple of years ago. We in the NPS Paleontology Program knew that the new edition of the Utah Geological Association's "Geology of Utah's Parks and Monuments" was not going to have an update of the overall park paleontology chapter. (Which is fair enough, since it was 35 pages in the previous update and was not getting shorter. The new volume is still well worth seeing, though, especially if you haven't seen the earlier editions.) We also were working with Tut Tran, then putting the finishing touches on the paleontological inventory report for Bryce Canyon National Park. These touches included some clever biostratigraphic figures of a kind we'd never used before. Thus was an idea born: Tut would prepare a standalone article featuring similar figures for the rest of Utah, with contributions from various luminaries in NPS and Utah paleontology. This article, "A Visual Paleontological Inventory of Utah’s National Park Service Areas", is now available for your edification and reading pleasure. Congrats, everyone!

Utah has 13 National Park Service units: five parks (Arches, Bryce Canyon, Canyonlands, Capitol Reef, and Zion), six monuments (Cedar Breaks, Dinosaur, Hovenweep, Natural Bridges, Rainbow Bridge, and Timpanogos Cave), one national recreation area (Glen Canyon), and one national historical park (Golden Spike). (There are a few other units in the state designated as "National", such as Grand Staircase-Escalante National Monument and Flaming Gorge National Recreation Area, but they are under different agencies.) This is omitting a few NPS trails (California, Mormon Pioneer, Old Spanish, and Pony Express) and the Virgin Wild and Scenic River, which are complicated to deal with because they don't have formal boundaries the same way the other types of units do; one day I'd like to go over rivers and trails thoroughly, but that's for another day. Anyway, the 13 units give Utah one of the best state-wide paleontological records in the NPS, up there with Alaska and California. Each one of them has something, although certainly some have more than others. The five national parks, Dinosaur NM, and Glen Canyon NRA are the most abundantly supplied and feature the longest records.

Figure 2, comparing the stratigraphic records of Utah's NPS units. Click to embiggen. CC BY 3.0 US.

These seven units are fairly similar stratigraphically and in fossil content, with the exceptions of Bryce Canyon (getting started when most of the others are tapering off) and to a certain extent Dinosaur (longer record and some different formations due to distance from the other units). The classic assortment of rocks generally includes the Permian, Triassic (Moenkopi and Chinle), Jurassic (Glen Canyon Group, San Rafael Group, and Morrison Formation), and part of the Cretaceous (Cedar Mountain Formation and Naturita, the old Dakota Sandstone). Arches, Canyonlands, Capitol Reef, and Glen Canyon in particular are geological and paleontological siblings. There are some older and some younger formations, but generally the sweet spot is between about 300 and 100 million years ago.

You might think, based on Dinosaur's reputation, that the Morrison Formation is the big producer, but as it turns out that's not the case. The Lower and Middle Jurassic rocks that make up so much of the scenic vistas, although not big bone producers, are perhaps the most iconic fossil producers with their fossil tracks. (Which is fitting for a park, because just like you can't put a vista in a box and take it somewhere else, fossil tracks are best appreciated where they are found.) The Chinle and Moenkopi are also good but a bit overlooked (Utah's Chinle having the excuse of being in the shadow of Arizona and New Mexico). Another interval that is very productive is the late Quaternary: several units have cave/rock shelter assemblages, usually thanks to packrats, with the assistance of other animals. Glen Canyon in particular is noted for dung caves, including Bechan Cave ("big feces" in Navajo) and its supply of mammoth dung. The Cretaceous is coming into its own with work at Bryce Canyon, Dinosaur, and Glen Canyon; in fact, work on the Cretaceous made our article outdated almost the day it was published, thanks to Pahasapasaurus gillettei from the Tropic Shale of Glen Canyon (Schmeisser McKean 2025). We were able to get October's Athenar bermani in there in the proof stage, but the plesiosaur managed to wait just long enough. (Darn it.)

This article is not a rewrite of the NPS paleontology chapters in the old UGA volumes. It sets out to do different things and is much more visual in focus, rather than textual. (It even has its own nifty cover image, done by artist Benji Paysnoe in the spirit of the great "Vertebrate Paleontology of Utah" volume.) The main things you will find in this that you won't find in the older chapters are Tut's outstanding diagrams and a grand 62-page appendix listing fossil taxa from each park unit by formation, with citations. Between the nine authors, I think we were able to put together a pretty darn comprehensive appendix, although doubtless we missed something. (If you spot something, let us know, so it can be included if we get the opportunity to do an update.) Me, of course, I'm hoping for more Paleozoic invertebrates, but I'm not turning up my nose at anything!

Figure 39, a sample diagram (Rainbow Bridge NM). You should go to the article to see what's been found at the big parks! CC BY 3.0 US.

We're all excited for this to be out, and we hope you find it useful as well, as a unique look at the paleontological riches of Utah's NPS units.

References

Schmeisser McKean, R. L. 2025. A new species of Pahasapasaurus (Plesiosauria: Polycotylidae) from the Upper Cretaceous Tropic Shale (lower Turonian) of southern Utah, U.S.A. Cretaceous Research 106269. doi: https://doi.org/10.1016/j.cretres.2025.106269.

Tran, T., A. R. C. Milner, J. S. Tweet, D. D. DeBlieux, R. Hunt-Foster, A. B. Shaffer, J. I. Kirkland, E. Warner-Cowgill, and V. L. Santucci. 2025. A visual paleontological inventory of Utah’s National Park Service areas. Geology of the Intermountain West 12: 221–292. doi: https://doi.org/10.31711/giw.v12.pp221-292.

Speleotherium logani

It would be easy to think that we've got the large Late Pleistocene mammals of North America pretty well locked down. After all, every self-respecting animal of that stripe has a long list of synonyms and pseudonyms, sometimes going well back into the 19th century. (All right, to be fair, horses are a mess if you look closely.) Even here, though, there can be surprises. Recently we had the Pacific mastodon and the re-establishment of the dire wolf in its own genus, and now we have the recognition of an entirely new genus and species of scrubox, Speleotherium logani (White et al. 2025).

If you know a bit of Greek, you'll get the idea that the name indicates we're dealing with a beast ("therium") associated in some way with caves ("speleo"). The holotype and best specimen of Speleotherium logani did indeed come from a cave, and in fact was partially encrusted with cave deposits (which certainly give it an unusual look but haven't made it easy to prepare or interpret). A few years ago the skull was photographed for a photogrammetric model, and you can take it for a spin and see the deposits, particularly on the right side of the face. This specimen and others were discovered in 1976 in what is now called Muskox Cave in its honor, within Carlsbad Caverns National Park, New Mexico. The species name honors the discover, Lloyd Logan. Although the name literally translates to "Logan's cave beast", the authors suggest the common name "Logan's austral scrubox" instead (White et al. 2025).

Figure 31 from Kottkamp et al. (2020), used in several other places as well (including White et al. 2025). You're looking at the back of the skull, going off to the right. Other bones are also visible, as well as the coating of cave mineralization.

The Muskox Cave fossils were long thought to belong to the shrubox Euceratherium (which is the name used for it at the 3D model above). That's how we labeled them in recent inventories of the park's fossils, for example (Kottkamp et al. 2020, 2022). It was not until White et al. began to prepare the specimens that it became apparent that there was something else here. Euceratherium has a narrow "forehead" and complexly twisted horn cores, whereas the Muskox Cave skull has a broad "forehead" and less curvy cores. The metapodials (metacarpals and metatarsals) are also shorter and stockier, which twigged something else; the authors knew of similarly proportioned metapodials of an animal similar to but much smaller than Euceratherium from sites in Mexico and Belize, but had never had a face to go with them. Speleotherium is therefore not a "one-off" but something that had a fairly wide range in North and Central America, and there are probably other examples that are currently listed as Euceratherium (White et al. 2025). The metapodial anatomy is rather similar to the same bones of the takin (White et al. 2025), which is a Himalayan bovid that's kind of in-between things like muskox, sheep, and goats in appearance and habits. That may give an idea of what Speleotherium was doing. The short and stocky metapodials suggest it was active in rugged terrain, but based on fossil distribution it was not limited to higher elevations (White et al. 2025).

The skull in the process of being captured by photogrammetry (producing the 3D model linked above), showing its best side. Figure 36 in Kottkamp et al. (2020).

Given we're dealing with National Park Service fossils, you can imagine it's been on my radar. It showed up in the 2001 inventory of NPS cave fossils as what is now a grainy photo (Santucci et al. 2001), but we've since been able to feature the image in higher resolution glory for Carlsbad-specific inventories (Kottkamp et al. 2020, 2022). There's been a soft spot for it around here; it even got a coloring page, now part of the "Cenozoic Life in the National Parks" coloring book (just mentally substitute Speleotherium for Euceratherium as the label; the coloring page was prepared long before the bones got their new name).

References

Kottkamp, S., V. L. Santucci, J. S. Tweet, R. D. Horrocks, E. Lynch, and G. S. Morgan. 2020. Carlsbad Caverns National Park: Paleontological resource inventory (public version). Natural Resource Report NPS/CAVE/NRR—2020/2148. National Park Service, Fort Collins, Colorado.

Kottkamp, S., V. L. Santucci, J. S. Tweet, R. D. Horrocks, and G. S. Morgan. 2022. Pleistocene vertebrates from Carlsbad Caverns National Park, New Mexico. New Mexico Museum of Natural History and Science Bulletin 88:267–290.

Santucci, V. L., J. Kenworthy, and R. Kerbo. 2001. An inventory of paleontological resources associated with National Park Service caves. NPS Geologic Resources Division, Denver. Technical Report NPS/NRGRD/GRDTR-01/02.

White, R. S., J. I. Mead, and G. S. Morgan. 2025. Logan's austral scrubox, a new ovibovine (Mammalia: Artiodactyla: Bovidae) from Muskox Cave, Eddy County, New Mexico. New Mexico Museum of Natural History and Science Bulletin 101: 473–494.

Hyoliths VII: The New Blood

Have you ever been working on some mundane task when you suddenly wondered about the latest news from the world of hyoliths? Taking a walk, or merging onto a busy highway, or applying shampoo in the shower? All right, probably not, but if so, we're here for you!

Appropriately for this time of year, we have some news of hyoliths meeting or escaping grisly demises. (Or not, but that's taphonomy for you.) Kraft et al. (2023) published on an exceptionally well-preserved specimen of the Middle Ordovician central European trilobite Bohemolichas incola, including gut contents. The hyoliths are only a small part (quite literally!) of the story, which is well worth checking out if you have any interest in trilobites. The small trilobite (on the order of 35 mm or 1.4 inches long) apparently ate every darn thing it could fit in its mouth that wasn't putting up too much of a fight, including tiny hyoliths, ostracodes, stylophoran echinoderms, and chunks of shells.

The trilobite in question (Figure 1 from Kraft et al. 2023; scale bar 10 mm or 0.4 inches). Hyolith bits are in purple, including one recognizable shell under the trilobite's pygidium (tail segment). CC BY 4.0.

Paleozoic examples of the bilobed trace fossil Rusophycus are often attributed to resting trilobites, and one of the things you can do when you're not moving is pick up a snack. Lee et al. (2025), in a description of Cambrian Rusophycus from China, included an example where the trace was associated with hyolith shells. Unlike classic Rusophycus, thought to occur at the seafloor surface, this example was interpreted as a burrow. Also unlike classic trilobite predation trails, in this case the food had a hard shell. The trace-maker is thought to have been scavenging for hyoliths that had been transported from elsewhere.

Returning to the Ordovician of central Europe, we find a hyolith that was not eaten, although not from lack of trying. Fatka et al. (2023) reported a specimen of Elegantilites custos with healed damage in the form of scratches on its operculum. The culprit in this case is thought to have been an echinoderm, possibly an ophiuroid (brittle star) trying to get in.

Perhaps you'd prefer to think of your hyoliths more in terms of a grand and proud lineage, rather than delicious treats for every passing trilobite and brittle star. If so, Liu et al. (2024) have an analysis of Cambrian hyoliths for you. Using all valid Cambrian genera (N=115), they considered a set of 20 morphological characteristics over time and space. Overall hyolith taxonomic diversity peaked in Series 2 of the Cambrian (roughly speaking, the time when trilobites appeared and therefore kind of like the old "Early Cambrian"). They then keeled over sharply and were at lower levels for much of the rest of the Cambrian, locally reviving to a certain extent in the Early Ordovician. Their decline may have been due to an ocean anoxic event (the Sinsk Event) around 513 to 508 million years ago. The two major wings of hyoliths, the hyolithids (the kind with helens and complex opercula; filter feeders?) and orthothecids (the kind without helens and with simple opercula; deposit feeders?), did not follow the same curves: the orthothecids peaked sooner and felt the bite sooner, whereas the hyolithids didn't really get started until Series 2 and actually peaked just after it before suffering their drop. Morphological diversity was greatest in Series 2, although granted hyoliths had a somewhat limited repertoire.

The curve of Cambrian hyoliths. Figure 1 in Liu et al. (2024). CC BY 4.0.

References

Fatka, O., M. Valent, and P. Budil. 2023. The first healed injury in a hyolith operculum. The Science of Nature 110(50). https://doi.org/10.1007/s00114-023-01879-0.

Kraft, P., V. Vaškaninová, M. Mergl, P. Budil, O. Fatka, and P. E. Ahlberg. 2023. Uniquely preserved gut contents illuminate trilobite palaeophysiology. Nature 622: 545–551. https://doi.org/10.1038/s41586-023-06567-7.

Lee, D.-C., M.‑K. Oh, Y. Zhang, X.‑L. Zhang, J.‑H. Lee, K. Liang, and W. Li. 2025. Two new probable feeding traces of Rusophycus from the Cambrian of China: tracemaker’s behavior and formation mode. Geosciences Journal 29: 1–17. https://doi.org/10.1007/s12303-025-00007-6.

Liu, F., T. P. Topper, L. C. Strotz, Y. Liang, Y. Hu, C. B. Skovsted, and Z. Zhang. 2024. Morphological disparity and evolutionary patterns of Cambrian hyoliths. Papers in Palaeontology 10(2). https://doi.org/10.1002/spp2.1554.

Your Friends The Titanosaurs: Utetitan zellaguymondeweyae

Back almost four years ago when we first waded into Alamosaurus, I noted that "I was waiting on it because I was concerned that it might suffer a taxonomic detonation at any time, so I thought I'd hold off as long as possible." Titanosaurs work on their own schedule. Although people have danced around the issue for decades by suggesting that A. sanjuanensis is dubious or refraining from including some specimens in the species, nobody had taken the step of formally proposing another name for any of the material until Gregory S. Paul in October 2025 with Utetitan zellaguymondeweyae. This genus and species are based on the North Horn specimen that has long been the "practical purposes" type* of A. sanjuanensis.

*Seems like there ought to be a name for non-type specimens that everyone uses instead of the type. "Apatotype", for "deceptive type"? Or "pseudotype" for "false type"? Think like the "Mantel-piece" of Iguanodon mantelli. Brachiosaurus had a whole apatotype species until it was split off for Giraffatitan.

Compact Thescelosaurus Year Ten

Twelve months have rolled along since our previous check on The Compact Thescelosaurus, now clocking in at a decade of existence. With Triassic and Jurassic pseudosuchians for the previous two years, the obvious addition was Cretaceous pseudosuchians, of which there were more than the previous two additions combined. The Cretaceous section wasn't quite so dominated by one group like the Jurassic was by thalattosuchians, but it was a great time to be a notosuchian.

Like this one, Simosuchus clarki. I took this photo when the traveling exhibit visited the Science Museum 11 years ago; Wikipedia is running a photo of the same mount from another stop on the itinerary.